ATL: ISAAC - Models

[BigEasy]

There is something very obvious going on the models are seeing. The further along Isaac goes, the better the models become. With that said, I still believe the final landfall will be around Mobile.

[smw1981]

Never heard of the RPM model. What is that and how reliable is it, typically?

BigB - This is pretty much all I could find about it..
"These high-resolution, 4km models are the same ones you see used during the weather segments on NEWS7. While some models are updated a few time a day, our RPM (Rapid Precision Mesoscale) model is updated with new data every 3 hours. While the data often shows just how the weather will unfold, it isn't the only source used for determining the upcoming weather.

In order to accurately predict the weather, we use over a dozen computer models to compare timing and forecast amounts.

If it were as easy as looking at one model, anybody could be a meteorologist."

[Hurricane Alexis]

The 0z guidance suggest it might pass just south of key west if you follow it through the middle.

[BigB0882]

I see a definite weakness on the 6hr NAM but is it closing or opening? Not as big as some other runs, I don't think.

[caneman]

L believe the models moved more West because of the storm speed. It had been going just 13 mph.

[caneman]

The trough was suppose to catch is but it may be more West before doing so

[BigEasy]

L believe the models moved more West because of the storm speed. It had been going just 13 mph.

Steering currents.

[BigB0882]

L believe the models moved more West because of the storm speed. It had been going just 13 mph.

Oh, ok, thank you. I have no idea if that is why but an interesting theory.

[ROCK]

L believe the models moved more West because of the storm speed. It had been going just 13 mph.

ding ding...you win a large prize!! .....exactly..speed is crucial here...any slow down effects upstream steering....

[ROCK]

The trough was suppose to catch is but it may be more West before doing so

the short wave is flatter....ridging remains thus the slow down and drift northward....

[MidnightRain]

I expect the models to swing back to the right, it's been this way all long....windshield wiping the whole Gulf coast.

[USTropics]

Never heard of the RPM model. What is that and how reliable is it, typically?

The Rapid Precision Mesoscale model (RPM) is a numerical weather prediction system based on the Advanced Research Weather Research and Forecast system (WRF-ARW). RPM generates forecasts out to 24 hours with updates every 3 hours in the United States and every 6 hours outside the United States. Precipitation forecasts are calculated from half-hourly instantaneous precipitation forecasts output by RPM. RPM model output is not available to the public.

[BigB0882]

L believe the models moved more West because of the storm speed. It had been going just 13 mph.

ding ding...you win a large prize!! .....exactly..speed is crucial here...any slow down effects upstream steering....

So here is a question. If it slows back down will the models shift back East or is the damage done, so to speak?

[StarmanHDB]

L believe the models moved more West because of the storm speed. It had been going just 13 mph.

ding ding...you win a large prize!! .....exactly..speed is crucial here...any slow down effects upstream steering....

This may or may not be the place to ask this (and please forgive me if it is the wrong place), but now seems very appropriate....Just what factors do affect a tropical cyclone's forward speed?

[USTropics]

L believe the models moved more West because of the storm speed. It had been going just 13 mph.

ding ding...you win a large prize!! .....exactly..speed is crucial here...any slow down effects upstream steering....

This may or may not be the place to ask this (and please forgive me if it is the wrong place), but now seems very appropriate....Just what factors do affect a tropical cyclone's forward speed?

Steering mechanisms. I.E. building ridges that 'drive' a storm or digging troughs that 'pull' a storm.

[BigB0882]

Will someone please be kind enough to interpret the NAM for us since we can't just look at where it puts Isaac. That would be ever so helpful.

[psyclone]

I expect the models to swing back to the right, it's been this way all long....windshield wiping the whole Gulf coast.

they have been swinging back and forth as they usually do but at some point they're going to lock in and stay there. in one hour we'll here what the pros at the NHC have to say about this latest significant shift with the models.

[LSU2001]

At some point the models stop doing the windshield wiper thing and settle into a pretty tight consensus. I am not saying that this will happen here but if the Euro comes on board with the westward track tonight you can pretty much bet that they will be close. If on the other hand, they shift back east then we will continue to lose sleep and continue to have to wait.
Tim

[smw1981]

At some point the models stop doing the windshield wiper thing and settle into a pretty tight consensus. I am not saying that this will happen here but if the Euro comes on board with the westward track tonight you can pretty much bet that they will be close. If on the other hand, they shift back east then we will continue to lose sleep and continue to have to wait.
Tim

I agree 100% Tim. Once the models stop moving east to west and back again (and they should fairly soon), it will mean they are in agreement and then I may get a little worried. But at this point, I am watching the trend, not the 00z or the 18z, but the overall picture.

I should note that I already put on my big girl briefs and battled the crowds at Wal-Mart, so I am ready either way.

[CYCLONE MIKE]

L believe the models moved more West because of the storm speed. It had been going just 13 mph.

ding ding...you win a large prize!! .....exactly..speed is crucial here...any slow down effects upstream steering....

So here is a question. If it slows back down will the models shift back East or is the damage done, so to speak?

Good question B. Is this getting to the point where speed stays around as is now, track shifts more west. If slows down for 24-48 hrs shifts more east?